Plant regeneration from hairy roots of apple rootstock, Malus prunifolia Borkh. var. ringo Asami, strain Nagano No. 1, transformed by Agrobacterium rhizogenes

Abstract

Stems of Malus prunifolia Borkh. var. ringo Asami strain Nagano No.1 were infected with Agrobacterium rhizogenes MAFF-02-10265, MAFF-02-10266, MAFF-03-01724 and MAFF-03-01725 by using a needle. The frequency of hairy root formation was 2.0% with both MAFF-02-10265 and MAFF-02-10266. Transgenic plants were obtained from hairy roots that were induced by A. rhizogenes MAFF-02-10265. Adventitious shoots were formed from the hairy roots on Murashige and Skoog medium, supplemented with 5.0 mg·liter-1 6-benzylaminopurine (BAP), 0.1 mg·liter-1 indole-3-butyric acid (IBA) and 0.1 mg·liter-1 gibberellic acid (GA3). These shoots developed abundant roots in the culture medium. The transgenic nature of the regenerated plants was confirmed by opine and PCR analysis. A transgenic plant, acclimatized in the greenhouse, showed prolific branching, miniaturized leaves, and shortened internodes.